Every morning I'm woken by parakeets. They scream across the gardens at the back of our road, brash, arrogant, decked out in flamboyant bright green, the revved-up teenagers of the neighbourhood, except that no teenager would be up and about at this hour. On sunny mornings, as they whoosh past in sixes and sevens, I imagine I'm in the foothills of the Himalayas, where the Indian ring-necked parakeet originated. But this is suburban south London.